1. Field of the Invention
This invention relates to tanks and more particularly to the venting of tanks subject to titling or listing such as marine fuel tanks.
2. Description of the Related Art
Since gasoline vapors present substantial safety hazards in marine vessel applications, gasoline fuel tank venting has long been known as a significant issue and has been addressed by many in the prior art. In addition to being a fire and explosion safety hazard, fuel vapor has also become an environmental issue.
The Environmental Protection Agency (EPA) has promulgated several regulations intended to reduce environmental pollution cause by gasoline vapors. These regulations have affected the methods and requirements in the production, storage, transportation and dispensing of gasoline.
These regulations have been extended to apply to marine engines. EPA regulation 40 CFR Chapter 1045 relates to the Control Of Emissions From Spark Ignition Propulsion Marine Engines and Vessels. EPA regulation 40 CFR Chapter 1060 relates to the Control Of Evaporative Emissions From New and In-Use Non-road and Stationary Equipment. These regulations established limits for the evaporative and diurnal (daily) emissions from marine gasoline fuel tanks. The EPA deferred the establishment of some of the testing requirements to the boating industry standards organization, The American Boat and Yacht Council (ABYC). The ABYC subsequently issued standard H-24 Gasoline Fuel Systems.
Applying the requirements of ABYC H-24 (tilt testing for ullage/air space) can result in fuel capacity losses up to or possibly exceeding 30% for some vessels. These extreme capacity losses are especially true if the vent fittings are located near the center of the fuel tank. Prior art solutions to this problem generally were addressed by several approaches.
To solve this problem of loss of fuel capacity, additional ullage vent valves or grade vent valves (at times two extra valves per tank) were placed at optimal vent locations on the fuel tank. However, U.S. Coast Guard regulations in 33 CFR 183.554 requires each fuel system fitting, joint and connection to located to be reached for inspection, removal, or maintenance without removal of permanent boat structure. Accordingly, multiple access plates had to be located at multiple locations to permit access to each of the ullage vent valves or grade vent valves. The multiple access plates results in unattractive decks, increased tooling costs and greater chance of leakage due to multiple fittings.
There have been several in the prior art who have attempted to solve these problems with varying degrees of success. None, however completely satisfies the requirements for a complete solution to the aforestated problem, wherein the ullage volume can be minimized while complying with the evaporative and diurnal regulations. The following U.S. Patents are attempts of the prior art to solve this problem.
U.S. Pat. No. 3,857,350 to Rohan discloses a fuel vent sump tank to prevent overboard spillage of fuel on marine craft comprising a sump tank connected to the fuel tank vent line, the vent line having a fuel flow alarm which informs an operator that fuel is being received into the vent line, the excess fuel being collected in the overboard vent sump tank. The collected fuel in the sump tank may be returned to the fuel tank. This system prevents accidental spillage or dumping of fuel overboard during the filling of the fuel tank or tanks.
U.S. Pat. No. 4,630,749 to Armstrong, et al. discloses a fuel fill tube for a vehicle fuel tank having a canister vapor vent, a shut-off valve and an overfill protection valve. The overfill valve prevents liquid from communicating with the carbon canister during overfill and communicates the liquid to the atmospheric open end of the fill tube.
U.S. Pat. No. 4,854,469 to Hargest discloses a pollution control device for marine fuel tanks including a conduit attachable to a fuel tank vent defined in the hull of a boat. The conduit is connected through an opening in a housing to an inlet tube which extends inside the housing. The floor of the housing slopes toward the inlet tube which has defined therein a liquid fuel outlet opening. A separation baffle extends from the top of the housing down toward the floor and away from the fuel outlet opening. On the side of the separation baffle opposite the side on which the inlet tube is disposed, a vapor opening is defined through the top wall of the housing. A flow turning baffle is disposed on the same side of the separation baffle as the vapor opening. A transparent section forms a portion of the housing sides and top that permits visual observation of the inlet tube, which extends into the housing to a height at a level higher than the level at which the free end of the separation baffle terminates. The flow turning baffle requires fuel to make a number of 180.degree turns before being able to exit through the vapor opening.
U.S. Pat. No. 5,035,729 to Hodgkins discloses a fuel tank venting system for a boat including a fuel tank the interior of which is open to a filler tube and a vent line. A liquid separation and recovery device is connected to the vent line and an outlet line which is open to atmosphere. Vapor delivered to the device through the vent line enters an inlet and passes through an opening. The vapor then passes through a screen, around a sphere that is buoyant in the liquid fuel, and escapes from the device through an outlet. When liquid fuel enters the device, the sphere rises blocking flow to the outlet. The trapped liquid passes through an opening into a cavity. The liquid entering the cavity displaces a spring loaded piston. When liquid is no longer being delivered to the cavity, the piston pushes the liquid back out the inlet and down the vent line to the fuel tank. In excess pressure situations, when liquid is being delivered to the device, a movable member is displaced upward opening a flow path to the outlet of the device through a second chamber. Once the over-pressure condition has subsided, the movable member returns to its original condition to prevent the passage of liquid through the device.
U.S. Pat. No. 5,327,946 to Perkins discloses a liquid fuel tank filling and venting device including a hollow body member containing a chamber, an inlet opening for supplying fuel downwardly into the chamber, a fuel outlet opening for supplying fuel from the chamber, and a vent opening connected with the chamber, each of the fuel outlet and vent outlets being independently connected with the fuel tank, whereby overflow fuel is returned to the chamber via the vent outlet. A fuel cap is provided for closing the inlet opening, the fuel cap containing a vent passageway including both a back-flame arresting screen and a fuel surge protector, so that the tank is normally vented to atmosphere when the fuel cap is in the closed position, but the venting passageway automatically closed upon the occurrence of a fuel surge, thereby avoiding undesirable fuel leakage.
U.S. Pat. No. 5,386,843 to Church discloses an apparatus for enabling the discharge of air and vapor from the head space of a fuel tank while preventing the discharge of liquid therethrough, having an inlet in communication with the head space and an outlet in connection with atmosphere. The apparatus has an internal chamber. A body is positioned above an orifice in a retainer inside the chamber. A relief element with an opening therethrough is positioned between the body and the outlet. When air and vapor flow through the device, Bernoulli's Principle causes the body to be suspended between the orifice and the opening in the relief element. When liquid enters the chamber, the body floats upward in the liquid and if the chamber fills with liquid, blocks the opening to prevent the discharge of liquid from the device. Liquid prevented from flowing out of chamber, flows back into the fuel tank when fluid is no longer being delivered into the device.
U.S. Pat. No. 5,469,800 to Brotz discloses a device and method for use when filling the internal fuel tank of a boat having an air outlet vent in fluid communication with the fuel tank with the air outlet vent exiting from a side of the boat's hull. The structure of the device is disposed in proximity to the air outlet vent for the collection and proper disposal of any overflow fuel exiting the air outlet vent to prevent its discharge into the water surrounding the boat.
U.S. Pat. No. 6,152,196 to Kehoe discloses a filling and venting system for a fuel tank which includes a canister having a fill section and a vent section defined therein. The fill section including a fuel inlet portion for the introduction of fuel thereinto and a fuel outlet portion configured to be attached to a fuel tank for directing fuel thereinto. The vent section includes a vapor outlet port configured to be attached to a vent and a vapor inlet port configured to be attached to the fuel tank to permit vapor to pass from the fuel tank, through the canister and to the vent. The vapor inlet port is configured to project into the fuel tank to a level below a level at which the fuel outlet port enters the fuel tank. A partition assembly includes a wall separating the fill section and the vent section. The wall includes an opening defined therein which permits fluid to flow therethrough. The partition assembly further includes a floatable sealing member which is disposed so as to cover the opening in the wall to prevent fluid flow therethrough when a level of liquid in the canister is below a predetermined value and to uncover the opening when the level of liquid is above the predetermined value.
U.S. Pat. No. 6,719,000 to Forsythe, et al. discloses a two-stage vent valve incorporated into a vehicle fuel distribution system. The vent valve is mounted to the top of a fuel tank of a motor vehicle in a vertically orientated position, so that a fluid inlet is in communication with the interior open air volume of the fuel tank, and an outlet is in communication with the exterior of the tank. The vent valve utilizes a two-stage valve mechanism to allow vapor to escape from the fuel tank, while preventing the leakage of liquid fuel during such operating conditions where the vehicle has tilted due to a small downgrade, sloshing of fuel in a full or near-full tank, or the event of a roll-over.
U.S. Pat. No. 6,866,056 to Scott discloses a fuel tank venting system including a fuel cap, a vent diaphragm and a vent disc. A valve cavity with a substantially concave bottom is formed in a bottom of the fuel cap. The vent disc preferably includes a disc flange and a diaphragm projection. At least one air passage is formed through the vent disc. A substantially convex surface is formed on a top of the diaphragm projection. The vent diaphragm is retained between the substantially concave bottom and the substantially convex surface. When air is needed for fuel flow, a vacuum within the fuel tank pulls the perimeter of the vent diaphragm downward, which breaks a seal with the substantially concave bottom. Air flows around the unsealed perimeter of the vent diaphragm through the at least one air passage. In a second embodiment, the fuel tank venting system is contained in a wall of the fuel tank.
U.S. Pat. No. 7,225,826 to Riviezzo discloses a simple fuel vent assembly for use in inboard and outboard fuel tanks for marine vessels. The vent assembly includes upper and lower portions defining an L shaped interior passageway. The lower portion includes upper and lower valve seats positioned within this passageway. Spaced vent openings extend through the lower portion above and below the valve seat. A spherical float is positioned within the passageway between the upper and lower valve seats. As fuel is added to the tank, pressure can escape through the fuel vent. The flow valve is within the passageway as the level of liquid fuel in the tank rises during the fuel refilling process. When the tank is at its desired fill level the float engages the upper valve seat and forms a seal preventing liquid fuel from traveling past the upper seat and through the passageway into the atmosphere outside the tank. The second vent opening remained open to vent pressure from the space between the top of the tank and the fuel level.
U.S. Pat. No. 7,380,542 to Herrington discloses an apparatus for preventing discharge of fuel from vent line when fueling a boat or other marine craft. A collection tank is mounted in the vent line from the main fuel tank, upstream of the overboard vent of the vessel. The collection tank includes a small, secondary reservoir within the main volume of the tank. Fuel escaping the main tank through the vent line enters the collection tank through two fitting, one being located in the bottom of the collection tank within the secondary reservoir and the other being located outside the reservoir; air displaced from the tank escapes to the overboard vent through an outlet fitting in the top of the collection tank. A float switch or other liquid level sensor is located within the secondary reservoir and is operatively connected to a warning light or other alarm device. Because the secondary reservoir is smaller than the main volume of the collection tank the fuel fills the reservoir first, and thus actuates the warning device well in advance of the main volume of the collection tank filling up with fuel that might escape through the overboard vent.
U.S. Pat. No. 7,422,027 to Riviezzo discloses a simple fuel vent assembly for use in inboard and outboard fuel tanks for marine vessels. The vent assembly includes upper and lower portions defining an L shaped interior passageway. The lower portion includes upper and lower valve seats positioned within this passageway. Spaced vent openings extend through the lower portion above and below the valve seat. A spherical float is positioned within the passageway between the upper and lower valve seats. As fuel is added to the tank, pressure can escape through the fuel vent. The flow valve is within the passageway as the level of liquid fuel in the tank rises during the fuel refilling process. When the tank is at its desired fill level the float engages the upper valve seat and forms a seal preventing liquid fuel from traveling past the upper seat and through the passageway into the atmosphere outside the tank. The second vent opening remained open to vent pressure from the space between the top of the tank and the fuel level.
U.S. Pat. No. 7,080,657 to Scott discloses a fuel tank venting system including a fuel cap, a vent diaphragm and a vent disc. A valve cavity with a substantially concave bottom is formed in a bottom of the fuel cap. At least one air passage is formed through the vent disc. A substantially convex surface is formed on a top of the diaphragm projection. The vent diaphragm is retained between the substantially concave bottom and the substantially convex surface. When air is needed for fuel flow, a vacuum within the fuel tank pulls the perimeter of the vent diaphragm downward, which breaks a seal with the substantially concave bottom to allow air flow. In a second embodiment, the fuel tank venting system is contained in a wall of the fuel tank. In a third embodiment, the fuel tank vent.
United States Patent Application 20100065137 to Armellino discloses a spill preventing system for vented marine fuel tanks incorporating a capture reservoir at the discharge end of the vent conduit extending from the tank. Any fuel forced into the vent conduit during the filling operation is temporarily retained within the capture reservoir and returned to the tank and is not ejected through the vent port into the environment.
United States Patent Application 20110308662 to Christopher, et al. discloses a ullage system for a marine fuel tank that maintains an exact ullage space in all marine refueling situations including refueling in moving or pitching and rolling situations. The invention includes two ball valve assemblies that are inserted into a fuel tank at approximately the same level. The two assemblies typically are at opposite ends of the tank. One of the ball valves is smaller than the other in diameter. The smaller valve is coupled to an air vent; the larger valve is coupled to the filler tube. An important feature of the present invention is that it can typically be made to fit any marine fuel tank simply by changing the length of a vent tube to reach the correct ullage level for the tank at hand. The components of the present invention can be made from standard fuel valve materials.
United States Patent Application 20120186453 to Gordon discloses a gas, diesel or other similar liquid fume or vapor filter apparatus specifically designed to be utilized in the marine environment e.g. motorized boats. The fume or vapor filter apparatus includes a housing with an input and output coupling mechanism designed to engage the input and output vent line.
Although the aforementioned prior art have contributed to the development of the marine art, none of these prior art patents have solved the above requirements imposed by new regulations.
Therefore, it is an object of the present invention to provide an improved tank vent for limiting the evaporative and diurnal emissions from marine gasoline fuel tanks.
Another object of this invention is to provide an improved tank vent for limiting the emissions from marine gasoline fuel tanks wherein fittings must are removable for maintenance and replacement without removal of permanent boat structure.
Another object of this invention is to provide an improved tank vent for enabling venting of the gasoline fuel tanks under various tilt requirements imposed for marine fuel tanks.
Another object of this invention is to provide an improved tank vent that is a cost effectively solution.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by modifying the invention within the scope of the invention. Accordingly other objects in a full understanding of the invention may be had by referring to the summary of the invention, the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.